Advice on Soil Pipe Vent Needed

[sotal]

Just moved into a new house, which has two toilets

The first toilet is upstairs in the bathroom and has a soil pipe which is inside the house (boxed in) and comes through the roof (all the houses round here are like that - approx 25 years old)

The Second Toilet is at the back of the house downstairs in the utility room/downstairs toilet, this toilet appears to go straight into the ground and has no vertical stack with a vent on it.

Now my plan is to add an en-suite bathroom above the utility room which puts the new toilet more or less directly above the downstairs toilet. My question is what do I do with the soil pipe? Do I need a vent on it? Should it have a vent on it? Can I have an internal vent with a one way valve on it or can I just go straight down into the ground like the downstairs one does?

Thanks in advance

 

[tryitandsee]

You will probably have a basin and bath as well in new bathroom, and for ease may want to put their wastes into the stack, in which case when flushing wc, may siphon out the water seals in the traps.
Use the durgo above the highest water level i,e, wc cistern. Same problem for everyone, where do you put it out of sight.

 

[sotal]

Does the vertical stack pipe need to be completely vertical?

One way I could make a really tidy job of it is to go verticle for the first two meters or so then go at 45 degrees for about 1m. The upstairs toilet would then join at the top of the vertical run and the 45 degree run would then just have the durgo on the top - would that be acceptable?

Also you mention that the durgo is required to allow air into the system - I've seen some small air admittance valves to go on the waste pipes from the toilet and the shower, can you use these? Or are they not OK as they wouldn't be above the highest water point?

Could the waste from the shower/sink go anywhere else? There is a hand basin downstairs which just goes out of the wall then is above a little drain which it is directed into with a short length of pipe - can this be done for showers/sinks???

Sorry for all the questions!

 

[tryitandsee]

What you have said sounds fine to me. Not sure if durgo can be angled at 45 degrees, others will advise on that, I'm not sure of the mechanical workings of them.
Again, not sure about these small anti syphon traps, wouldn't have thought they would let enough air in quickly enough. I think I saw somewhere that 100mm stack can be vented with a minimum 75mm pipe. Don't quote me on that though. The idea of keeping the durgo higher is for flooding. Which I question, because it would come back through the WC anyway!

Just seems that all pipework into stack would be neater, externally (there are many ways to skin a cat

 

[Nige F]

Durgo can`t be @ 45 degrees ........but you might find that Hep V O valves and a small aav ........would comply .........have a google for the waste valves and ask your Build Officer if the website findings look favourable